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attribute highp vec2 vPos;
attribute highp vec4 vData; // x = time, y = lifeSpan, z = size, w = endSize
attribute highp vec4 vVec; // x,y = constant speed, z,w = acceleration
uniform highp mat4 qt_Matrix;
uniform highp float timestamp;
varying lowp float fFade;
void main() {
highp float size = vData.z;
highp float endSize = vData.w;
highp float t = (timestamp - vData.x) / vData.y;
highp float currentSize = mix(size, endSize, t * t);
if (t < 0. || t > 1.)
currentSize = 0.;
gl_PointSize = currentSize;
highp vec2 pos = vPos
+ vVec.xy * t * vData.y // apply speed vector..
+ 0.5 * vVec.zw * pow(t * vData.y, 2.);
gl_Position = qt_Matrix * vec4(pos.x, pos.y, 0, 1);
highp float fadeIn = min(t * 10., 1.);
highp float fadeOut = 1. - max(0., min((t - 0.75) * 4., 1.));
fFade = fadeIn * fadeOut;
}
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